ETC HE Report 2022/10: Health Risk Assessment of Air Pollution and the Impact of the New WHO Guidelines

This report estimates the health risk related to air pollution in 2020 based on the latest Air Quality Guidelines published by the World Health Organization. The estimates consider the number of premature deaths and years of life lost related to exposure to fine particulate matter, ozone and nitrogen dioxide across Europe. A sensitivity analysis to the changes in concentration-response functions and counterfactual concentrations is performed to understand the impact of the new Air Quality Guidelines on the mortality outcome estimates. The sensitivity analysis also includes the concentration response functions discussed in the ELAPSE study, a review on the latest European epidemiological studies.

28 Nov 2022

Joana Soares, Alberto González Ortiz, Artur Gsella, Jan Horálek, Dietrich Plass, Sarah Kienzler

This report estimates the mortality related to air pollution in 2020 based on the latest Air Quality Guidelines (AQG) published by the WHO, using the concentration-response functions (CRF) for PM2.5, NO2, and O3, and the AQG levels recommended for PM2.5 and NO2. The estimates show that the largest relative mortality risk is observed in central and eastern Europe for PM2.5, central and southern Europe for NO2, and south and eastern Europe for O3. The lowest impact is found in northern and north-western Europe. The mortality attributed to air pollution in 2020 compared to 2019 increased for PM2.5 and decreased for NO2 and O3. Apart from the changes in concentrations and demographics, the COVID19 pandemic seems to also have an influence on these changes: the reduction in PM2.5 concentration was counteracted by the excess of deaths due to the pandemics, and the reduction in NO2 concentration as a result of the lockdown measures was more impactful in reducing mortality than the increasing impact of excess of deaths.

Changing assumptions on CRF and counterfactual concentrations have implications in the final estimates of mortality health outcomes. The sensitivity analysis shows that it is not straightforward to assess which assumptions estimate the highest health impacts when both factors change. In this case, the outcome will depend on the concentration at the grid-cell level. The new CRFs are expected to reduce the health outcomes for NO2 and increase for PM2.5 and O3, when compared to the previous ones. However, increasing counterfactual concentrations from 0 to 5 µg/m3 for PM2.5, decreases the estimations, and decreasing from 20 to 10 µg/m3 for NO2, increases the estimation. Overall, when aggregated to all countries, the health outcomes with the new assumptions are, if compared to the old assumptions, reduced by over 40 % for PM2.5 and increased by 50 % and 30 % for NO2 and O3, respectively, in 2020.